1. Technical Field
The present invention relates in general to distributed data processing systems and in particular to distributed data processing systems with cluster-aware virtual input/output servers (VIOSes). Still more particularly, the present invention relates to a method, data processing system and computer program product that enable election of primary nodes within a VIOS cluster.
2. Description of the Related Art
Virtualized data processing system configuration, which provides the virtualization of processor, memory and Operating System (OS) resources are becoming more and more common in the computer (and particularly the computer server) industry. To a lesser extent, storage virtualization is also known and provided in limited environments. However, within the virtualization computing environment, storage virtualization and management is implemented as a separate virtualization model from server virtualization and management. One important component within this storage virtualization model is the virtual input/output server (VIOS), which supports I/O operations for one or more clients within the distributed computer system. In a large scale distributed computer system, there can be a very large number of VIOSes individually providing access to different clients. With this configurations of separate VIOSes supporting separate clients, different client logical partitions (LPARs) associated with different virtualized server systems may access the same storage access network (SAN) storage. However, the client LPARs on one server do not have any “knowledge” of whether the SAN disk that the client LPAR is trying to access is being used by some other client LPAR belonging to the same server or another server. The conventional implementation of distributed server systems providing storage virtualization within shared SAN storage can cause data integrity issues and may potentially cause data corruption and client partition crashes.